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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "instruction_set_features_arm64.h"
     18 
     19 #include <fstream>
     20 #include <sstream>
     21 
     22 #include "android-base/stringprintf.h"
     23 #include "android-base/strings.h"
     24 
     25 #include "base/logging.h"
     26 #include "base/stl_util.h"
     27 
     28 namespace art {
     29 
     30 using android::base::StringPrintf;
     31 
     32 Arm64FeaturesUniquePtr Arm64InstructionSetFeatures::FromVariant(
     33     const std::string& variant, std::string* error_msg) {
     34   // Look for variants that need a fix for a53 erratum 835769.
     35   static const char* arm64_variants_with_a53_835769_bug[] = {
     36       // Pessimistically assume all generic CPUs are cortex-a53.
     37       "default",
     38       "generic",
     39       "cortex-a53",
     40       "cortex-a53.a57",
     41       "cortex-a53.a72",
     42       // Pessimistically assume all "big" cortex CPUs are paired with a cortex-a53.
     43       "cortex-a57",
     44       "cortex-a72",
     45       "cortex-a73",
     46   };
     47   bool needs_a53_835769_fix = FindVariantInArray(arm64_variants_with_a53_835769_bug,
     48                                                  arraysize(arm64_variants_with_a53_835769_bug),
     49                                                  variant);
     50 
     51   if (!needs_a53_835769_fix) {
     52     // Check to see if this is an expected variant.
     53     static const char* arm64_known_variants[] = {
     54         "cortex-a35",
     55         "exynos-m1",
     56         "exynos-m2",
     57         "denver64",
     58         "kryo"
     59     };
     60     if (!FindVariantInArray(arm64_known_variants, arraysize(arm64_known_variants), variant)) {
     61       std::ostringstream os;
     62       os << "Unexpected CPU variant for Arm64: " << variant;
     63       *error_msg = os.str();
     64       return nullptr;
     65     }
     66   }
     67 
     68   // The variants that need a fix for 843419 are the same that need a fix for 835769.
     69   bool needs_a53_843419_fix = needs_a53_835769_fix;
     70 
     71   return Arm64FeaturesUniquePtr(
     72       new Arm64InstructionSetFeatures(needs_a53_835769_fix, needs_a53_843419_fix));
     73 }
     74 
     75 Arm64FeaturesUniquePtr Arm64InstructionSetFeatures::FromBitmap(uint32_t bitmap) {
     76   bool is_a53 = (bitmap & kA53Bitfield) != 0;
     77   return Arm64FeaturesUniquePtr(new Arm64InstructionSetFeatures(is_a53, is_a53));
     78 }
     79 
     80 Arm64FeaturesUniquePtr Arm64InstructionSetFeatures::FromCppDefines() {
     81   const bool is_a53 = true;  // Pessimistically assume all ARM64s are A53s.
     82   return Arm64FeaturesUniquePtr(new Arm64InstructionSetFeatures(is_a53, is_a53));
     83 }
     84 
     85 Arm64FeaturesUniquePtr Arm64InstructionSetFeatures::FromCpuInfo() {
     86   const bool is_a53 = true;  // Conservative default.
     87   return Arm64FeaturesUniquePtr(new Arm64InstructionSetFeatures(is_a53, is_a53));
     88 }
     89 
     90 Arm64FeaturesUniquePtr Arm64InstructionSetFeatures::FromHwcap() {
     91   const bool is_a53 = true;  // Pessimistically assume all ARM64s are A53s.
     92   return Arm64FeaturesUniquePtr(new Arm64InstructionSetFeatures(is_a53, is_a53));
     93 }
     94 
     95 Arm64FeaturesUniquePtr Arm64InstructionSetFeatures::FromAssembly() {
     96   UNIMPLEMENTED(WARNING);
     97   return FromCppDefines();
     98 }
     99 
    100 bool Arm64InstructionSetFeatures::Equals(const InstructionSetFeatures* other) const {
    101   if (kArm64 != other->GetInstructionSet()) {
    102     return false;
    103   }
    104   const Arm64InstructionSetFeatures* other_as_arm64 = other->AsArm64InstructionSetFeatures();
    105   return fix_cortex_a53_835769_ == other_as_arm64->fix_cortex_a53_835769_ &&
    106       fix_cortex_a53_843419_ == other_as_arm64->fix_cortex_a53_843419_;
    107 }
    108 
    109 uint32_t Arm64InstructionSetFeatures::AsBitmap() const {
    110   return (fix_cortex_a53_835769_ ? kA53Bitfield : 0);
    111 }
    112 
    113 std::string Arm64InstructionSetFeatures::GetFeatureString() const {
    114   std::string result;
    115   if (fix_cortex_a53_835769_) {
    116     result += "a53";
    117   } else {
    118     result += "-a53";
    119   }
    120   return result;
    121 }
    122 
    123 std::unique_ptr<const InstructionSetFeatures>
    124 Arm64InstructionSetFeatures::AddFeaturesFromSplitString(
    125     const std::vector<std::string>& features, std::string* error_msg) const {
    126   bool is_a53 = fix_cortex_a53_835769_;
    127   for (auto i = features.begin(); i != features.end(); i++) {
    128     std::string feature = android::base::Trim(*i);
    129     if (feature == "a53") {
    130       is_a53 = true;
    131     } else if (feature == "-a53") {
    132       is_a53 = false;
    133     } else {
    134       *error_msg = StringPrintf("Unknown instruction set feature: '%s'", feature.c_str());
    135       return nullptr;
    136     }
    137   }
    138   return std::unique_ptr<const InstructionSetFeatures>(
    139       new Arm64InstructionSetFeatures(is_a53, is_a53));
    140 }
    141 
    142 }  // namespace art
    143